1. Field of Invention
The present invention relates to a fan, a motor and a stator structure thereof, and more particularly to a fan with axial-winding and radial-induction, and its motor and stator structure.
2. Related Art
Accompanying to the development of technology, the electronic apparatus has become an indispensable product at home or office in the daily life. The motor is widely used in the electronic apparatus, which can effectively convert the electric energy into the mechanical energy.
The motors may be classified into many types. A conventional brushless motor structure includes a rotor structure and a stator structure. The rotor structure is fitted into a bearing of the stator structure. The stator structure interacts with a permanent magnet of the rotor structure to generate an alternating and rotating magnetic field to enforce the rotor structure to rotate.
The brushless motors may be classified into an axial-winding and axial-induction motor and a radial-winding and radial-induction motor according to the coil winding method and the induction manner. As shown in FIG. 1, the axial-winding and axial-induction brushless motor 1 has a stator structure 20 which includes a coil set 202 made of windings with predetermined number of turns, a magnetic base 203 and a circuit board 204. The stator structure 20 interacts with a permanent magnets 101 attached to an upper inner surface of a rotor structure 10 to produce the axial-induction. As shown in FIG. 2, coils of a radial-winding and radial-induction brushless motor 1 are wound around pole arms 205 of a stator structure 20, and interact with the magnetic field formed by a permanent magnet 101 attached to the circumferential inner wall of a rotor structure 10.
However, for the axial-winding brushless motor 1 as shown in FIG. 1, because of the restricted space of the motor, the number of winding turns of the coil set 202 and the magnetic area A cannot be simultaneously increased. That is, in the restricted space, the greater number of winding turns is, the less magnetic area A becomes in the coil set 202, which will influence the effect of the magnetic force. In addition, the permanent magnet 101 of the rotor structure 10 and the magnetic base 203 of the stator structure 20 induce an attractive force with each other due to the axial-induction. Thus, the force applied to the bearing 201 of the motor is too large, and the structure of the magnetic base 203 may deform. For the radial-winding brushless motor 1 as shown in FIG. 2, because the coils have to be wound around the pole arms 205 and the spaces between the pole arms 205 are restricted, the winding of the coils is inconvenient and the speed of winding the coils is limited. Furthermore, the distribution of the magnetic field generated by the coils is not uniform, and the weight of the suspended pole arms 205 plus coils causes the large loading to the central support of the motor.
It is thus imperative to provide a fan, a motor and a stator structure thereof capable of solving the above-mentioned problems.